A certain type of wiring board is known in the art that has a substrate having a cavity formed therein and an electronic component disposed in the cavity. The wiring board further includes an insulating layer formed to cover the opening of the cavity (see Japanese Patent Application Publication No. 2011-216740, for example).
As described above, a related-art wiring board has a single electronic component disposed in a single cavity.
Placing a plurality of electronic components in a single cavity may give rise to a risk of causing the electronic components to be displaced at the time of filling an insulating layer in the cavity. Such displacement of the electronic components is associated with a risk of having short-circuit caused by physical contact or a risk of having a failure to secure connection with a wiring layer, thereby creating a problem regarding electrical reliability.
Accordingly, it may be desirable to provide a wiring substrate and a method of making the wiring substrate that ensure improved electrical reliability with respect to a plurality of electronic components disposed in a single penetrating hole.